For many years, silica-based fillers have been used in a variety of products to improve properties including, but not limited to, color properties, anti-blocking properties, and tensile properties in, for instance, polymer and coating applications. Certain qualities that enhance a filler's performance—such as, for example, fine particle size, high brightness, low oil absorption—are desirable in many commercial applications, and fillers possessing those characteristics generally have much higher commercial value than those that do not.
Silica is available in both crystalline and amorphous forms, and can be of natural origin or synthetically produced. Crystalline silica has been reported in some cases to have potentially harmful health effects, and so has become disfavored in many end uses. Synthetic silica is generally more expensive than natural silica.
Accordingly, there is a need for a natural amorphous silica filler product with one or more beneficial characteristics including, but not limited to, fine particle size, low oil absorption, and high brightness, but lacking the high crystalline silica content and high cost associated with many synthetic mineral fillers, which may be used in at least one of a variety of filler applications. The commercial values of such products, because of their unique characteristics, would be expected to be much higher than for conventional diatomite and perlite filter products currently on the market.